Industrial control and automation systems are often used to automate large and complex industrial processes. These types of systems routinely include wireless networks that facilitate communications with a wide range of industrial field devices. The field devices can include wireless sensors, wireless actuators, and wireless controllers.
After a wireless field device is deployed, a user may need to identify where the field device is located for service, recovery, or replacement. However, locating a wireless field device can be challenging since there are no physical wires that can be traced to find the field device.
Locating a wireless field device is typically accomplished via triangulation. In this approach, neighboring wireless nodes near the field device measure the strengths or directions of wireless signals received from the field device. The locations of the neighboring nodes and the received signal strengths or directions are then used to estimate the field device's location. Unfortunately, this approach may be impractical in various circumstances. For instance, the number of reachable neighboring nodes may be too small to permit triangulation of the field device's location. Also, the estimated location may not be accurate enough to actually locate the field device, such as in a complex facility. In addition, this approach cannot be used if the field device is unable to transmit wireless signals (such as due to a failed power supply).